1. Field of the Invention
This invention finds its application in the field of resin molding compounds which are used in a wide variety of commercial applications from automotive parts, household appliances to business machines.
2. Description of the Prior Art
Resin molding compounds have been used for many years to produce molded products in the building construction and automotive fields. For example, automotive hoods, front grille elements, doors and other panels are now being made of molded resin to replace metal stamped parts. Not only does the use of resin molding technique enable greater design flexibility but there can be a great reduction in the number of individual parts or components. Other resin molded parts are rapidly finding their way in the consumer field as casings or housings for small appliances and in the business world as business machine housings and cabinets.
It is known that the resin component of the molding compounds is an expensive ingredient and adds to the cost of the finished product in greater proportion than any other ingredient. Thus, it is well-known technique to add fillers of various kinds to the resin to replace much of the resin with a view to economy. Obviously, for the same physical characteristics of a given molding compound, the greater the amount of filler, the more economical will be the ultimate product. Conversely, if, for the same amount of filler, a given filler will impart improved molding properties to the resin compound, for the same cost, greater flexibility in molding technique will be found. In other instances improvement in molding properties by a suitable filler will result in greater penetration of the resin compound into reinforcing ingredients such as glass fibers or filamentary mats.